Pete C. wrote:

Which renders the door with the same - albeit slightly stronger -
protection as those piddly chain-locks that can be defeated with
bolt cutters slid through the cracks.

A much better scheme is brackets on either side and a 2x4 between
the two.

Even better is a diagonal brace from the door to some stopping point
some feet away (i.e., wall).

If you REALLY want to do it, there are doors with moveable pins
attached to the doorknob that sink into all four sides of a door,
much like the bolts in a safe door..

Even more fun, Browning has an actual safe door that is disguised as a
normal 6 panel residential door, and comes complete with a remote
electronic lock control.

Cool!

The Texas Prison system (and maybe others) has a division called "Texas
Prison Industries." It makes stuff.

The "stuff" is "sold" to other government agencies in the state. Amongst the
"stuff" they make are (heh) doors. Here are some:

http://www.tci.tdcj.state.tx.us/prod...S/default.aspx

It's a hoot to prowl around the site looking at all the neat stuff made by
the inmates - from school busses to saddles. I understand the prison system
itself is amazingly self-supporting. They grow their own food (except for
such things as coffee and pepper) including cattle, eggs, pork, etc. They
grow cotton, gin it, turn it into cloth, and make uniforms, clothing,
mattresses, etc. Quite an operation.

When an inmate "graduates," he's often learned a useful skill, such as
hoeing cotton, gathering eggs, making grits, and so forth. Lest you shrug
that off, imagine how hard it is to collect enough eggs for 175,000 inmates'
breakfast!